Polylactide (PLA) Waste SustRecPLA (2014)

Bioplastic Waste – SustRecPLA (2014)

Since years the amount and diversity of products made from biobased plastics is continuously increasing, especially in the packaging segment. Actually polylactide (PLA) is the most important biobased polymer on the packaging market and because many concepts use PLA as composite material or in blends, the recycling of PLA-containing waste streams is very difficult with conventional processes (e.g. re-granulation), if not impossible.

The information of German consumer associations describes the dilemma very explicitly:”Because bioplastics can actually not be recycled and hinder the recycling of other plastics, they should not be placed into the “yellow bag” (for packaging plastics waste) or the recycling bin. The German Environmental Agency actually recommends the disposal via the residual waste. Then bioplastics can at least be incinerated with energy recovery3)“. And even though the term “bio” generally has a positive connotation, the disposal industry over and over again expressed concern, that PLA can disturb the established plastic recycling.

Therefore the objective of the research project “SustRecPLA” was the recovery of clean and high-quality PLA recyclates from post-consumer waste. The project was funded by the German Agency for Renewable Resources (FNR) and the German Federal Ministry of Food and Agriculture (BMEL) and started in November 2014.

Eight project partners including Fraunhofer IVV worked within the scope of this project. On one hand the solvent-based CreaSolv® Process was optimized for selected PLA waste streams1) and on the other hand compared with mechanical recycling (recompounding) in regard to the quality of the recyclates and the economic viability.

The examined PLA originated from industrial and post-consumer waste and the CreaSolv® Technology allowed the production of PLA recyclates without significant differences to virgin material in regard to injection molding tests2). With an approximately 50% higher yield this process offers a substantial economic advantage.

Based on their comprehensive work the project partners were able to demonstrate that there exist different options for PLA recycling. The findings provide a good basis for the inclusion of PLA waste into established recycling streams and therefore come just at the right time, because the new regulations of the Packaging Law will come into effect on 1st January 2019.

Which main advantages do bioplastics really offer?

In our current language the prefix “bio” stands for two properties: “biobased” and “biodegradable”. Biobased products are manufactured partially or completely from renewable raw materials. These products can be biodegradable or not biodegradable. According to DIN EN 13432 biodegradable means, that a material is capable of being decomposed by more than 90% to water, carbon dioxide (CO2) and biomass within a defined period of time at defined temperature, oxygen and humidity conditions in the presence of micro-organisms or fungi4). For biobased plastics we need of course cultivation areas, which are becoming increasingly scarce with a growing world population and its increasing food requirements and biodegradable bioplastics decompose to water and the greenhouse gas CO2, that contributes to global warming. So the same is generated as during an incineration. Even the German Environmental Protection Agency therefore describes it as a “bluff package” and recommends – together with Environmental Action Germany (DUH) – the incineration of bioplastic waste, because this allows at least an energetic recovery5,6). Due to problems during the composting German municipalities refuse as a general rule the disposal of bioplastics with the biowaste7).

Conclusion

Bioplastics sounds „sustainable“, but competent authorities and environmental organizations consider them as a problem. However one can recycle such plastics with the CreaSolv® Process just as other thermoplastic polymers, so that they can be fully reused again and will not get lost as a resource in a Circular Economy.